This invention is in the field of fluid control valves. More particularly, it is in the field of valves which can be assembled from components so as to provide a variety of combinations of chambers and controls.
In the prior art there are many types of valves such as gate, globe, butterfly and ball valves and there are many types of operators or actuators for remote control such as pneumatic, hydraulic, electromechanical and electrohydraulic. Some of the actuators or operators are fail safe, in the sense that failure of power to the actuator will cause the valve to return to the original position. Some of the valves are balanced, in the sense that difference between upstream and downstream pressure on the valve does not affect the actuating force required, or has a minor or minimum effect on the actuating force. This valve is unique in that it is fully balanced except for the slight unbalance due to pressure on the cross-sectional area of the valve stem, in both the two way and three way versions. Since the valve is balanced, it requires minimum actuating force, making it possible to use a smaller, lighter, less expensive and less power consuming actuating means.